engine overheat prevention alarm

[92EcoDiesel Jetta]

I bought one of these http://cgi.ebay.com/ebaymotors/Automobile-Multimeter-Gauge-EGT-Boost-Water-oil-/200469434194?pt=Motors_Car_Truck_Parts_Accessories&hash=item2eace8cf52 with the intent of sounding an alarm (loud buzzer) when the engine is beginning to overheat, before the onset of permanent engine damage. Where do you suggest I install the sensor for a fool proof warning?  Coolant temp? Cylinder head temp? Oil temp?

[dankcorey22]

I have one of those in my car im rebuilding... For EGT's tho. But my buzzer is not set up for max EGT's

[CRSMP5]

what i do...

things to think of...

coolent temp ONLY works if coolent present.. aka spring leak.. gauge no work... sensor reading air.. so i add a sensor to my waterpump housing as even if i spring a leak.. there is something to read..

oil temp.. only works if oil passing it.. so room in oil filter housing issue if you got normal oil temp gauge.. cannot build a T for 2 sensors.. so your kinda screwed unless your using that as the gauge..

egt will require a pre turbo sensor.. lack of room if you got a egt gauge.. room for 1 sensor is iffy at times..

so me i just use gauges..

now if you got a car with factory ac.. or even the front water neck for car with ac.. you can use the ac kill sensor to kill the fuel pump power if it overheats.. wire fuel pump wire to one side.. other goes to pump.. yea that simple.. but again.. no water it may lag/not work..

maybe construct your own bypass hose.. one from water pump to head.. add in that sensor to run your thinggy there..

[BigVWman]

oil temp.. only works if oil passing it.. so room in oil filter housing issue if you got normal oil temp gauge.. cannot build a T for 2 sensors.. so your kinda screwed unless your using that as the gauge..

I don't have any input on where to use the Op's gizmo, but on the T 42draft designs sells an oil pressure T and even a relocation kit, i run the T on my a1 cabbyTdi
Trying to keep an alarm for self destruct is tough because there are so many ways you could kill it. Maybe use past experience and pick whatever you know your prone to screw up!

[92EcoDiesel Jetta]

Agree that it is not possible to have an alarm to prevent every conceivable types of engine damage, which is not what I am after. I am looking for a warning to prevent engine overheating from loss of coolant, which happened to me when the coolant level warning light failed to come on. As pointed out, the sensor must be in contact with coolant to give an accurate reading. Maybe the best place is monitoring cylinder head temp? Will that give an early enough warning before the head gasket blows and the head starts to warp?

[CRSMP5]

oil pressure can run on a t no issue.. temp.. no..

well knowing your whole waterpump question.. think it was you.. at least.. if you pull the housing.. you can drill and tap the back of the housing.. spend some time looking where the sensor can fit.. it does trust me.. aka the brass stock style from pre plastic waternecks.. 10x1.0 thread.. this will give you the best reading of coolent.. there is only 1 good spot for it.. and it fits there like a glove.. and no i lack pics.. still need to add that sensor to my toaster..

[ORCoaster]

If I had this monitoring device and was worried about overheating I would stick it down low near/in the waterpump housing.  My reason is that is the lowest place in the system and will have water warming up if you do spring a leak.  The temperature would go up soon there if you start loosing water.  So just set the alarm to go off a few degrees over what would be your normal driving temp.  Monitor it for a bit to figure out what the temp normally is then set a few degrees above it. 

There are cylinder head gauges and those may give you better information but getting a setup to work seems more involved than the water pump.

Personally I use gauges, real numbers mean more to me than high or low, H-C.  I watch them often enough that I learn what is a "normal temp.' for the type of driving I am doing.  Just the other day I questioned why the water temp was higher in town than when I drive on the highway.  I thought my fan was ts up but as it turn out it was working just fine.  I just don't do a lot of stop and go driving in the 80 degree temps.  I just had to learn that was normal.

[CRSMP5]

orcoaster... what waterpump do you have? stamped steel impeller or cast? and if stamped steel which one.. small diameter or big?

yea i know 3 types... each has a variation..

cast is best.. most stable.. no real variation.. just hardest to find..
small diameter stamped runs hotter, less flow at higher rpm.. aka highway..
big diameter stamped, not seen one in 15 or so years.. most flow.. at higher rpm.. warmer at low rpm.. aka round town..

things i have noticed over the years via temp gauge at pump..

[nathan_b]

I can send you 10 cast impeller water pumps any time of the day!

**secret** meyle is the only major brand that I can find that makes all theirs cast.

[R.O.R-2.0]

I can send you 10 cast impeller water pumps any time of the day!

**secret** meyle is the only major brand that I can find that makes all theirs cast.

really? ill take all 10, delivered at 4am, on a sunday!!

lol, kidding aside, thats kinda cool you can get cast impellers still..

[vanbcguy]

If you're looking to kill a few birds with one stone, here's an idea:



Acme Gold Anodized,
3 sensor, VW diesel
rear water outlet housing
(1.6 & 1.9TD AAZ engines).

You need this rear outlet housing at the back of your VW head if you don't have a metal housing. The metal housings don't warp and provide grounding for sensors eliminating extra wiring.

ACME VW diesel water temp housings are anodized for corrosion resistence and come with a new VW temp sensor (for glow plug relay), Suzuki temp sensor (for your stock temp gauge) and an aftermarket port so you can utilize an aftermarket water temp gauge as needed.

Saw this on the ACME Adapters site the other day.  That electronic gauge can definitely work with the Suzuki-style temp sender (or really anything else you can think of!!).  No idea what the pricing is for the housing by itself but it looks like an EXCELLENT idea for those of us with the stupid plastic ones.

[CRSMP5]

i know you can nathan... just gotta be carefull as they sell both cast and stamped.. why i been getting them thru your shop... else i get stamped ones..

perty neck.. issue is leak = non proper reading.. what he is trying to resolve..

[ORCoaster]

CRSMP5 now you are going to make me crawl under that car and look at the waterpump?  I was going to anyway as on my trip down from Portland tonight I was running real cool, under the 70 C mark on the gauge until I stopped long enough for a p break and the temp went up to 85 and held there.  I was on the slower part of the route near towards the coast by that time.  Once I dropped 10 mph off the speed the engine seems to warm up a bit.  Likely get better mileage for it too.

I like that multiport neck and may look into buying one as I really have need for an additional sensor for the VDO gauge I salvaged for a GTI.  I have it tapped into the one for the glow plugs and it makes them stay on for a few seconds after the engine starts.  Not a bad feature but it also turns the glows on no matter how hot it is outside. 

Have to get back to you on the type of WP.  It is dark and scary out right now.

[fatmobile]

I bought one of these http://cgi.ebay.com/ebaymotors/Automobile-Multimeter-Gauge-EGT-Boost-Water-oil-/200469434194?pt=Motors_Car_Truck_Parts_Accessories&hash=item2eace8cf52 with the intent of sounding an alarm (loud buzzer) when the engine is beginning to overheat, before the onset of permanent engine damage. Where do you suggest I install the sensor for a fool proof warning?  Coolant temp? Cylinder head temp? Oil temp?

 The '91 Jetta has an overheat warning light in the dash doesn't it?
 Shares the low coolant flashing light.

[BigVWman]

to get around the leak or loss of coolant not giving you a reading couldn't you do the fancy acme neck in conjuction with a normally closed circuit through the coolant so that when its level drops it would also signal the warning? Similar to what they use for idiot light on level sensor for overflow bottle? Knowing that hot water rises would it be possible to still overheat a head if you were monitoring at the lower stat housing?Especially since the coolant wouldn't be making a its rounds up top if it had dropped and the cast iron blocks take considerably longer to heat up than the aluminum head? Just askin, and following intently since I have always wanted to devise a shut down to keep the SIL from killing another vw(idiot lights and gauge warnings are meaning less if she has someplace to go)!